In the United States of America over 240 million cars and light trucks travel the roads and highways. If one includes Canada, the number of cars and light trucks increases to 259 million. Almost all these vehicles have equipment to protect against theft of the vehicle or theft of property in the vehicle. Most vehicles at least have mechanical locks for doors and trunks that allow a person to unlock them using a simple mechanical key. Some vehicles have electronic locking systems that allow persons to enter security codes using keypads on the externals of the vehicles, such as on the doors, in order to gain access. In addition to these mechanical locks and electronic keypad-based systems, a significant number of vehicles also have remote control access devices that allow users to press a button and activate the mechanical locks of the doors and trunks, as well as other items of the vehicle, such as horns and dome lights. These remote control devices are alternatively referred to as remote keyless entry (RKE) systems.
A standard remote-control lock system, or RKE system, for a motor vehicle generally has a transmitter, normally carried by the owner of the vehicle, a receiver mounted in the vehicle, and some type of a control circuit coupled to the receiver which activates mechanical locks for the doors and trunks. The transmitter usually has a code word generator that produces a changing code word created from a number of binary code bits, a modulator that applies the code word to a signal, and an output unit that takes the modulated signal and transmits it to the receiver. The receiver generally has a front-end signal sensing circuit that picks up the transmitter modulated signal, a demodulator that extracts any code word from the signal, and a processing unit that compares the extracted code word with a stored code word and actuates the mechanical locks or other devices when the received and stored code words match.
The signal transmitted between the transmitter and receiver is usually a radio frequency (RF) signal, such as an ultra-high frequency signal. However, other types of signals are used, such as infrared light signals or even ultrasonic sound signals. In the RF and infrared signal systems, various signal modulation and conditioning techniques are employed, such as amplitude modulation, frequency modulation, pulse width or pulse duration modulation, and phase shift keying. The vast majority of RKE systems employ unidirectional communication. In other words, the transmitter held by the vehicle owner only sends information to the receiver in the vehicle that only receives information. Even so, some systems do employ bidirectional communication methods, such that the remote device and the control device in the vehicle both transmit and receive information.
In order to prevent a thief from intercepting the signal transmitted from the transmitter to the receiver, with such a device as a scanner, and later reproducing the signal to gain access to the vehicle, various methods of protection have been employed. Some systems provide a table of codes that the transmitter and receiver cycle through, such that single individual codes are used infrequently and may not be used successively to gain access. These systems generally include encrypted code bits that keep the transmitter and receiver in synchronization. Alternatively, in other systems, the transmitter and receiver step through the code tables based on a reference to the current time.
Some systems employ an authentication routine to protect against unauthorized access. For example, a system employing one type of an authentication routine may generate changing code from the transmitter in such a manner that only a specially configured receiver can intelligently decode the transmitted signal and act upon it. This unidirectional coding and decoding technique, known as the fixed code method, uses a secret of base number and an algorithm stored in both the transmitter and the vehicle receiver. By means of the algorithm, successive items of code information can be derived from the base number, allowing the vehicle receiver to authenticate the transmitter.
Although keyless entry systems have been well developed and considered useful for supplementing, or even sometimes eliminating the need for, mechanical keys, the existing systems in use today all have drawbacks. One major problem, which affects millions of users every year, is the problem of locking keys inside the vehicle. Almost all of the devices in use today, from mechanical keys to remote keyless devices, are rendered useless once locked inside the confines of the vehicle. Keypad access systems attached to the vehicle provide a remedy for this problem, but keypad systems have also had numerous drawbacks. First, users often forget the security codes. Second, many users do not even take the time to program the codes into the systems in the first place. Another major problem with the remote access control systems in use today is the lack of configurability. In other words, the systems are generally proprietary and require that an owner return to the vehicle dealership or other equipment manufacturer to obtain a specially designed replacement access device, which often employs proprietary hardware. More often than not, owners must pay hefty prices in order to purchase remote access devices that will operate the locks on their vehicles. Obviously, a vehicle owner who has locked the vehicle keys in the car may resort to calling a locksmith, but doing so will cost the owner for every incident. Additionally, owners are often in a hurry and generally do not have time to wait on a locksmith.
One solution available to vehicle owners who lock their keys inside their car is the solution afforded from satellite vehicular access systems. Vehicle owners who choose to pay a monthly subscription fee to a service provider may regain access to their vehicle by calling the service provider. After a short authentication process, the service provider may unlock the vehicle by transmitting an unlock command from a satellite system to the vehicle. Many times, this particular process may be initiated via a cellular telephone belonging to the vehicle owner. Today, such telephones and other wireless devices generally do not interact, or communicate, directly with vehicles in any significant way.
Given the methods and systems available for remotely controlling vehicular devices, such as those which grant access to vehicles, and the associated drawbacks with each of them, vehicle owners need alternative methods and systems that enable them to securely communicate with, and gain access to, their vehicles using alternative wireless devices that are readily available. Such methods and systems for remotely controlling vehicular devices should be configurable by the owners and allow greater freedom with a wide selection of access devices, without requiring special hardware cards, monthly subscription fess, or human intervention.